Find AI if AC= AG, BE = 10, and AC = 4

In a recent year, one United States dollar was equal to about 82 Japanese. How many Japanese yen are equal $100?$1,000?$10,000
Given is:

1 USD = 82 Japanese Yen  

Conversion:

1.  100 USD x 82 JY / 1 USD = 8, 200 Japanese Yen
2.  1000 USD x 82 JY / 1 USD = 82, 000 Japanese Yen
3.  10, 000 USD x 82 JY / 1 USD = 820, 000 Japanese Yen